Wyoming Cave Dig Reveals Hundreds of Ice Age Fossils

A Wyoming cave has turned up hundreds of fossils of animals that roamed the Americas around the time of the last Ice Age. The fossils range from small creatures like lizards and snakes to megafauna like bison.

"We found evidence of bison, a bit of gray wolf and quite a lot of cheetah and horse," paleontologist Julie Meachen, who led a team of international researchers on a recent dig, told Reuters.The two-week dig ended on Friday.

Meachen spearheaded the two-week exploration of the cave, called Natural Trap Cave, which was first discovered in the 1970s and hasn’t been studied since. The only entrance is a 15-foot hole in the ground that’s now covered by a metal grate, according to the Associated Press. The researchers believe the animals whose bones are preserved below stumbled into the hole and fell to their deaths. The drop to the ground is about 85 feet.

The cold, damp conditions inside the cave kept the animals' remains well preserved, according to Reuters. Studying the fossils could reveal information about the last Ice Age extinction, which occurred about 10,000 years ago. The remains are between 12,000 and 23,000 years old.

"Some bones still have collagen with intact DNA for genetic testing and some fossils are fragments crushed by rocks," Meachen told Reuters. "But we take it for what it is when we find it."

During the dig, two animals slipped through the grate covering the hole — a deer mouse, which survived and was sent back to the surface, and a pack rat, which died. The researchers left the pack rat’s body where it fell and plan to observe it over time to understand the decay rate inside in the cave.

More than 30,000 fossils have been removed the cave since its discovery, according to the U.S. National Park Service's web site, including mammoths, lions and camels. No evidence of human activities has been found in the caves, leading researchers to believe the hole, which is difficult to spot from a distance, was once located along a migratory corridor. Layered sediments in the cave have revealed that the region went from a glacial climate to its current desert climate in just 500 years.

"It's an incredible site," Brent Breithaupt, a paleontologist for the U.S. Bureau of Land Management (BLM), told the Associated Press. “It definitely is one of the most significant sites that BLM manages, and it will provide very, very important information."